Acromyrmex

is the more diverse of the two leafcutting ant genera (the other is Atta). These distinctive spiny insects cut fresh vegetation to feed to a specialized fungus that grows only in ant nests. The fungus serves as the ants' food source and in return is cultivated and dispersed by the ants. Like all fungus-growing ants, Acromyrmex is found only in the new world tropics and subtropics.

Acromyrmex striatus

Leafcutter ants don't normally fight with other types of ants, but they can be brutal towards other leafcutters. Here, a trio of Acromyrmex striatus workers team up to kill an Atta saltensis leafcutter that has wandered into their territory.
Santiago del Estero, Argentina